The present invention relates to microbial preparations for crop production, specifically microbial inoculants incorporated in carriers that provide protection for the colonizing microorganisms and the method for producing the same.
In theory, microbial inoculants, without human intervention, have a low survival rate and efficiency in their natural soil environment because of the insufficient colony forming units per gram soil. Since the 1950s, biofertilizers that have an increased colony increased inoculum potential concentration have been developed and commercialized. There are three basic types of biofertilizers: liquid-phase, suspension- or, solid carrier-based microbial inoculants. Commercial biofertilizers effectively enhance soil fertility because they contain sufficient cells of efficient strains of specific microorganisms, that can fix atmospheric nitrogen, solubilize/mineralize phosphorous and potash or decompose organic wastes and augment plant growth with hormones and other growth promoting substances with their biological activities.
The present invention is a carrier-based biofertilizer that promotes growth of plants of any type of terrestrial biome, using special biological inoculants, such as plant growth promoting rhizobacteria. The invention induces extensive root and root hair formation, enable plants to efficiently use soil nutrients, supply plants with nitrogen from the air, increase drought tolerance and protect the plants from pathogens. Further, the inoculants can be mixed with an insecticide or fungicide without any appreciable decrease in effectivity.
The closest prior art are reported in WO 2007/014974 (“Aseptic Mycorrhization Inoculant and In vitro and Ex vitro Application Methods”), WO 1994/006732 (“Method for Obtaining a Wettable Powder Inoculant for Use with Leguminous Crops”), WO 2006/070061 (“Stable Microbial Inoculants and Methods for Production of Them”), WO 2002/015702 (“A Thermo-stable Bio-matrix”), and WO 2000/034440 (“Microorganisms for Improving Plant Productivity”).
According to WO 2007/014974 (“Aseptic Mycorrhization Inoculant and In vitro and Ex vitro Application Methods”), a low-viscosity, light, semi-solid agar-type base culture medium is used to facilitate the penetration of the root in the inoculant, as well as to potentiate and preserve the infectiousness of arbuscular mycorrhizal fungi, such as those of the present invention. WO 2007/014974 sought to obtain the advantage of being as effective in in vitro as well as ex vitro inoculation by using a semi-solid inoculant. However, it is gel-based and has a short shelf-life, which the present invention seeks to address.
WO 1994/006732 (“Method for Obtaining a Wettable Powder Inoculant for Use with Leguminous Crops”) reports a method for obtaining a wettable powder inoculant formulation for use with leguminous crops, comprising the industrialization of an inoculants for leguminous from a centrifugated biological mass of Rhizobium spp twice immersed in a cryogenic protective solution rich in sugar and protein which is subjected to a lyophilization method. Like the present invention, it is formulated with substances rich in polysaccharides and associated with a cellular protector which substitutes the previously used peat support. It also has a long shelf life of up to 25 months even when stored at room temperature. However, WO 1994/006732 can only be used for leguminous crops. Further, the formulation of the carrier uses sugar and protein while the present invention uses milk and glycerin. Also, WO 1994/006732 does not teach that the powder inoculant with a pest protectant such as an insecticide.
WO 2006/070061 (“Stable Microbial Inoculants and Methods for Production of Them”) teaches away from the present invention. It describes water containing microbial inoculants in paste form with shelf life of at least 3 months, preferably 12 months. It reports that drying, which is a method utilized in the present invention is complicated, expensive and may even be impossible.
WO 2002/015702 (“A Thermo-stable Bio-matrix”) reports a method for producing a thermo-stable biodegradable medium for storage of biological materials wherein the biological material includes: a pesticide; a viricide; a bactericide; a fungicide; and a combination of these. While the method is similar in that the biological material can be safely mixed with potentially degradative substances such as pesticides, viricides, bactericides, fungicides or a combination of these, the medium is structurally different because it is gel-based and contains a biopolymer selected from the group of xanthan gum, acacia gum, guar gum, gellan, starch or a combination thereof, unlike the present invention which is in powder form. Thus, it is no surprise that WO 2002/015702 discloses a maximum shelf life of only eighteen (18) months, which is considerably shorter than that of the present invention which allows storage of at least three (3) years.
WO 2000/034440 (“Microorganisms for Improving Plant Productivity”) is directed to microbes which includes the microorganism Azospirillum brasilense, which belongs to the same genus as some of those in the present invention. As with the present invention, two specific strains of microbial inoculant of WO 2000/034440 is effective for increasing the productivity of both nonlegume and legume plants as well as vegetable plants over a wide variety of soil types and climates. However, the WO 2000/034440 is narrowly directed only to the Azospirillum brasilense, a microorganism not covered by the present application. Further, it does not teach an inventive carrier nor the method of production that prolongs its shelf life.
The present invention, the microbes, method and product, are absolutely different and improve over other known methods and products and have considerable advantages over the nature and quality of the methods and products, particularly in the storage life of the microbial preparation.